Apparatus for evaporating liquid



Fatented Nov. 1 0, 1931 UNITED STATES PATENT OFFICE RAYMOND N. EHRHART,OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T ELLIOTT COM- PANY, 0FPITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA APPARATUS FORnvaron'arme LIQUID App1ication filed June 3, 1926. Serial No. 113,428.

The present invention relates broadly to the art of liquid treatment,and more particularly to an improved apparatus for effecting therecovery of waste heat, and utilizing such heat for evaporating liquid.

' It is will recognized in the art to Which my invention broadlyrelates, that in the utilization of high pressure steam for thedevelopment of energy in mechanical orother forms, the steam in passingthrough the apparatus with which it is being utilized, gives up acertain portion of its thermal energy. The portion so given up to theapparatus is in turn converted thereby into another form of energy,such, for example, as mechanical energy. The greater portion of thethermal energy of steam is not utilized by the apparatus, so that thedischarge therefrom, or the steam rejected thereby, carries by far thegreater part of the original thermal energy. In other words, the thermalenergy in the exhaust of an apparatus such, for example, as a steamengine, is usually many times that which has been utilized by theengine, and this thermal energy of exhaust steam 1s usu ally spoken ofas degraded or low level heat.

In accordance with standard, principles of operation, in order to obtainthe maximum range for the utilization of heat, it is desirable to havethe engine discharge or exhaust into a region of the lowest possiblepressure, which, with steam, means the lowest possible temperature. Acondenser is an artifice generally utilized to create such a region oflow temperature and pressure, the temperatures maintained by thecondenser being generally so low that there is no way to utilize all ofthe low level heat in therange as maintained by 43 the condenser. I havefound that it is possible to reclaim small portions of the low levelheat which have heretofore ordinarily been rejected to the condenser,and the pres ent invention has to do particularly with this 45reclaiming and utilization of such portions of the heat.

In the accompanying figure of the drawing, which figure is largelydiagrammatical, there is illustrated one embodiment of the presentinvention, which embodiment comprises the combination of a condenser andevaporator in which the heat for evaporation is supplied by exhauststeam, the. heat of which under ordinary conditions of operation wouldnormally be given to the condensing water of the main condenser.

In carrying out the present invention, there may be provided a mamcondenser 2, having 1 a header at one end, divlded by a transverse Abovethe tube nest 6 I provide a partition 9 above which are located twosupplemental tube nests 10 and 11. That portion of the cooling waterwhich is not discharged through the ofi -take 8 passes upwardly to thetubes 10, and flows therethrough to the, opposite end of the condenser.his then returned through the tubes 11, discharging into thesupplemental water olftake 12. It will be apparent that the tube nests10 and 11 are so located that they are directly exposed to the steamentering the main condenser through the inlet 7. It is usually foundthat tubes first facing the vapor flow have the highest heat transfer,and those farthest removed from the vapor flow, the lowest heattransfer. Under such conditions, the tubes in the nests 10 and 11. will.have a more efficient heat transfer than the tubes in any other part ofthe main condenser. By selecting proper water quantities and flowvelocities through these two nests of tubes, I can obtain such anefficient transfer of heat from the vapor to the water passingtherethrough that the water leavin through the supplemental connection12 will have a temperature almost equal to that of the temperature ofthe vapor delivered to the condenser. In other words, I preferably soproportion the entire condenser that the tion arise from the provisionof a method and apparatus by means of which a'portion of the low levelheat may be recovered and effectively utilized instead of discarding thesame, as has heretofore been practiced.

Other advantages of the invention arise from the provision of a maincondenserhaving auxiliary tube nests of such construction thattemperature conditions therein may approximate the temperatureconditions of the supplied steam, and delivering water from such tubenests to a flash chamber in which is maintained a flash temperaturegradient sutficient to effect flashing of a portion of the liquid sodelivered.

Still further advantages arise from the combination of a flash chamberreceiving water heated by low levelheat to substantially the temperatureof the exhaust steam, and having relatively low pressure maintainedtherein by suitable means, such as a high vacuum condenser.

I have described a preferred embodiment ofthe invention, but it will beunderstood that it is not to be limited, since it may be otherwiseembodied or practiced within the scope of the following claims:

I claim 1. Evaporating apparatus comprising a main condenser, auxiliaryheating tubes within the condenser and subjected to the pressureconditions therein, means for passing a portion of the cooling water forsaid condenser through said auxiliary tubes, a

flash chamber means for deliver ng the water from said auxiliary tubesto the flash chamber, and means for maintaining in said flash chamber apressure lower than the pressure in the vapor space of said condenser.

2. Evaporating apparatus comprising amain condenser, auxiliary heatingtubes within the condenser and subjected to the pressure conditionstherein, means for pass; ing a portion of the cooling water for saidcondenser through said auxiliary tubes, a flash chamber means fordelivering the water from said auxiliary tubes to the flash chamher, andmeans for maintaining in said flash chamber a pressure lower than thepressure in the vapor space of said condenser, said last named meanscomprising a high vacuum condenser.

3. Evaporating apparatus comprising a main condenser, auxiliary heatingtubes within the condenser and subjected to the pressure conditionstherein, means for passing a portion of the cooling water for saidcondenser through said auxiliary tubes, a flash chamber means fordelivering the water from said auxiliary tubes to the flash cham ber,and means for maintaining in said flash chamber apressure lower than thepressure in the vapor space of said condenser, said last named meanscomprising a high vacuum.

condenser in combination with gas" exhausting means.

4. Evaporating apparatus comprising a main condenser having main tubesand auxiliary tubes within the condenser and subjected to the pressureconditions therein connected to provide a series flow of watertherethrough, means for admitting water first to the main tubes, meansintermediate the main and auxiliary tubes for taking off a portion ofsuch water and permitting only a portion thereof to pass through theauxiliary tubes, and means for producing a steam flow in series oversaid tubes.

5. Evaporating apparatus comprising a main condenser having main tubesand auxiliary tubeswithin the condenser and sub j ected to the pressureconditions therein connected to'provide a series flow of watertherethrough, means for admitting water first to the main tubes, meansintermediate the main and auxiliary tubes for taking off a portion ofsuch water and permitting only a portion thereof to pass through theauxiliary tubes, and means for producing a steam flow in series oversaid tubes, with the steam contacting first with the auxiliary tubes.

6. Evaporating apparatus comprising a main condenser having main tubesand auxiliary tubes within the condenser and subjected to the pressureconditions therein con nected to provide a series flow of watertherethrough, means for admitting water first to the main tubes, meansintermediate the main and auxiliary tubes for taking oil a portion ofsuch water and permitting only a portion thereof to pass through theauxiliary tubes,

said auxiliary tubes having ahigher heat transfer coefficient than themain tubes, and means for producing a steam flow in series over saidtubes.

7. Evaporating apparatus, comprising a main condenser casing having aninlet for a vapor mixture, main tubes and auxiliary tubes in said casingboth subjected to the pressure conditions obtaining in the condenser andconstructed to provide a series flow of water therethrough with the flowfirst through the main tubes, said auxiliary tubes being disposedadjacentsaid inlet with the main tubes remote therefrom, and meansintermediate the main and auxiliary tubes for taking oif a portion ofthe Water and permitting only a portion to pass through the auxiliarytubes.

Intestimony whereof I have hereunto set my hand.

RAYMOND N. EI-IRHART.

